Energy management system for hybrid electric vehicles

• US 6,230,496 B1
• Filed: 06/20/2000
• Issued: 05/15/2001
• Est. Priority Date: 06/20/2000
• Status: Expired due to Term

• Current Assignee: BAE Systems Controls Incorporated (BAE Systems Plc)
• Original Assignee: Lockheed Martin Integrated Systems Incorporated (Martin Marietta Corporation)
• Inventors: Hofmann, Lee Gregor, Peterson, William Anders, Roden, Garey George
• Primary Examiner(s): NGUYEN, HOANG M
• Application Number:
  US09/597,636
• Time in Patent Office: 329 Days
• Field of Search: 606/98, 607/06, 180/65.1, 180/65.2, 180/65.3, 180/65.4, 180/65.5
• US Class Current: 60/706
• CPC Class Codes: B60K 6/105 the accumulator being a flywheel
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/32 characterised by the fuel cells
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/26 Vehicle weight
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/622 by satellite navigation
• CPC Class Codes: B60L 2240/642 Slope of road
• CPC Class Codes: B60L 50/30 using propulsion power stored mechanically, e.g. in fly-wheels
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/40 : for controlling a combination of batteries and fuel cells
• CPC Class Codes: B60W 20/00 : Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/11 : using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 20/12 : using control strategies taking into account route information estimation or calculation of non-directly measurable driving parameters B60W40/00
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2530/10 : Weight
• CPC Class Codes: B60W 2555/40 : Altitude
• CPC Class Codes: B60W 2556/50 : of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 2710/06 : Combustion engines, Gas turbines
• CPC Class Codes: B60Y 2200/143 : Busses
• CPC Class Codes: F01B 21/04 : the machines or engines being not all of reciprocating-piston type, e.g. of reciprocating steam engine with steam turbine
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/40 : Application of hydrogen technology to transportation, e.g. using fuel cells
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/907 : Electricity storage, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/908 : Fuel cell

Abstract

An energy control unit for a hybrid vehicle is operable to control stored energy of an energy storage unit such that the energy level of the hybrid vehicle is maintained substantially at a desired magnitude. The energy level of the hybrid vehicle is a function of at least: (i) mechanical kinetic energy of the hybrid vehicle; (ii) mechanical potential energy of the hybrid vehicle; and (iii) potential energy of the energy storage unit.

Claims

1. An energy control unit for a hybrid vehicle, the hybrid vehicle including an electric motor operable to provide a source of drive power to the hybrid vehicle, an energy storage unit operatively coupled to the electric motor to provide a first source of energy to the electrical motor, and a prime mover operatively coupled to the electric motor to provide a second source of energy to the electric motor, the energy control unit being operable to control an amount of stored potential energy of the energy storage unit such that an energy level of the hybrid vehicle is maintained substantially at a desired magnitude, the energy level of the hybrid vehicle being a function of at least:

(i) mechanical kinetic energy of the hybrid vehicle;

(ii) mechanical potential energy of the hybrid vehicle; and

(iii) potential energy of the energy storage unit.

2. The energy control unit of claim 1, wherein the energy storage unit is taken from the group consisting of at least one battery, at least one ultra-capacitor, at least one lossless inductor, and at least one flywheel.

3. The energy control unit of claim 1, wherein the prime mover is taken from the group consisting of internal combustion engines, gas turbine engines, steam engines, and fuel cells.

4. The energy control unit of claim 1, wherein:

the prime mover is operable to convert potential energy contained in fuel into the second source of energy; and

the energy level of the hybrid vehicle is not a function of the potential energy of the fuel.

5. The energy control unit of claim 1, wherein the energy control unit is operable to maintain an average of the energy level of the hybrid vehicle substantially at the desired magnitude.

6. The energy control unit of claim 1, wherein the energy level of the hybrid vehicle is proportional to an aggregate of:

(i) the mechanical kinetic energy of the hybrid vehicle;

(ii) the mechanical potential energy of the hybrid vehicle; and

(iii) the potential energy of the energy storage unit.

7. The energy control unit of claim 1, wherein the energy control unit is operable to compare an estimated energy level of the hybrid vehicle with a desired magnitude and control the stored potential energy of the energy storage unit in response to the comparison such that the energy level of the hybrid vehicle tends toward the desired magnitude.

8. The energy control unit of claim 7, wherein the energy control unit operates at a relatively low bandwidth of about 0.0001 to 0.0010 Hertz such that the energy level of the hybrid vehicle tends toward the desired magnitude at a relatively low rate.

9. The energy control unit of claim 7, wherein the energy control unit is operable to estimate at least one of the mechanical kinetic energy of the hybrid vehicle, the mechanical potential energy of the hybrid vehicle, and the potential energy of the energy storage unit.

10. The energy control unit of claim 9, wherein the energy control unit includes at least one of:

a mechanical energy estimation unit operable to estimate the mechanical kinetic energy and mechanical potential energy of the hybrid vehicle; and

an energy estimation unit operable to estimate the potential energy of the energy storage unit.

11. The energy control unit of claim 9, wherein the energy control unit is operable to estimate the mechanical kinetic energy of the hybrid vehicle to be substantially proportional to a product of hybrid vehicle weight or mass and a square of hybrid vehicle velocity.

12. The energy control unit of claim 11, wherein the energy control unit is operable to at least one of:

(i) estimate the hybrid vehicle weight or mass by aggregating a base vehicle weight or mass with at least one of an estimate of passenger weight or mass and an estimate of fuel weight or mass; and

(ii) use a stored estimate of the hybrid vehicle weight or mass.

13. The energy control unit of claim 11, wherein the energy control unit is operable to at least one of:

(i) estimate the hybrid vehicle velocity based on a speed measurement from a speed sensor; and

(ii) estimate the hybrid vehicle velocity based on information received from at least one source external to the hybrid vehicle.

14. The energy control unit of claim 13, wherein the energy control unit is operable to estimate the hybrid vehicle velocity based on obtaining radar reflection measurements and employing a Doppler algorithm.

15. The energy control unit of claim 14, wherein the energy control unit is in communication with a Doppler unit of the hybrid vehicle, the Doppler unit being operable to produce radar source signals and receive radar reflection signals to produce the radar reflection measurements.

16. The energy control unit of claim 13, wherein the vehicle speed sensor includes a speedometer system.

17. The energy control unit of claim 13, wherein:

the at least one source external to the hybrid vehicle includes a Global Positioning System (GPS) operable to provide radio signals which contain information concerning a longitudinal and latitudinal position of the hybrid vehicle; and

the energy control unit is operable to receive the radio signal information concerning the position of the hybrid vehicle and obtain an estimate of the hybrid vehicle velocity by calculating differences in position of the hybrid vehicle over time.

18. The energy control unit of claim 9, wherein the energy control unit is operable to estimate the mechanical potential energy of the hybrid vehicle to be substantially proportional to a product of hybrid vehicle weight or mass and an altitude of the hybrid vehicle.

19. The energy control unit of claim 18, wherein the energy control unit is operable to at least one of:

(i) estimate the hybrid vehicle weight or mass by calculating a quotient of an estimated force and an estimated acceleration of the hybrid vehicle; and

(ii) use a stored estimate of the hybrid vehicle weight or mass.

20. The energy control unit of claim 18, wherein the energy control unit is operable to at least one of:

(i) estimate the altitude of the hybrid vehicle as being proportional to a time integral of a grade angle of a surface on which the hybrid vehicle travels multiplied by a velocity of the hybrid vehicle;

(ii) receive an estimate of the altitude of the hybrid vehicle from an altitude sensor; and

(iii) estimate the altitude of the hybrid vehicle based on information received from at least one source external to the hybrid vehicle.

21. The energy control unit of claim 20, wherein the energy control unit is operable to at least one of (i) estimate the grade angle by estimating a force required to move the hybrid vehicle on the grade angle and calculating the grade angle therefrom;

(ii) receive an estimate of the grade angle from a grade angle sensor; and

(iii) estimate the grade angle based on information received from at least one source external to the hybrid vehicle.

22. The energy control unit of claim 21, wherein the grade angle sensor includes at least one of a vertical gyro and an inclinometer.

23. The energy control unit of claim 21, wherein the at least one source external to the hybrid vehicle includes bar-coded placards disposed proximate to the surface on which the hybrid vehicle travels, wherein bar-codes of the placards contain the information concerning the grade angle of the surface.

24. The energy control unit of claim 21, wherein the at least one source external to the hybrid vehicle includes at least one radio device, wherein radio signals propagate from the at least one radio device which contain the information concerning the grade angle of the surface.

25. The energy control unit of claim 21, wherein:

the at least one source external to the hybrid vehicle includes a Global Positioning System (GPS) operable to provide radio signals which contain information concerning a longitudinal and latitudinal position of the hybrid vehicle; and

the energy control unit is operable to receive the radio signal information concerning the position of the hybrid vehicle and obtain an estimate of the grade angle of the surface based thereon.

26. The energy control unit of claim 25, wherein the energy control unit includes a database containing a plurality of grade angles which are indexed by and retrievable using the information concerning the position of the hybrid vehicle.

27. The energy control unit of claim 25, wherein the energy control unit is operable to communicate with a database external to the hybrid vehicle, the external database containing a plurality of grade angles which are indexed by and retrievable using the information concerning the position of the hybrid vehicle.

28. The energy control unit of claim 27, wherein the energy control unit is operable to (i) communicate with the external database via a wireless communication channel;

(ii) transmit the information concerning the position of the hybrid vehicle to the external database over the wireless communication channel; and

(iii) receive the grade angles from the external database over the wireless communication channel.

29. The energy control unit of claim 20, wherein the altitude sensor includes a altimeter.

30. The energy control unit of claim 20, wherein the at least one source external to the hybrid vehicle includes bar-coded placards disposed proximate to the surface on which the hybrid vehicle travels, wherein bar codes of the placards contain the information concerning the altitude of the hybrid vehicle.

31. The energy control unit of claim 20, wherein the at least one source external to the hybrid vehicle includes at least one radio device, wherein radio signals propagate from the at least one radio device which contain the information concerning the altitude of the hybrid vehicle.

32. The energy control unit of claim 31, wherein:

the at least one source external to the hybrid vehicle includes a Global Positioning System (GPS) operable to provide radio signals which contain information concerning the altitude of the hybrid vehicle; and

the energy control unit is operable to receive the radio signal information concerning the altitude of the hybrid vehicle and obtain an estimate of the altitude of the hybrid vehicle based thereon.

33. The energy control unit of claim 9, wherein the energy storage unit is an electrical energy storage unit and the energy control unit is operable to estimate electrical potential energy of the electrical energy storage unit to be substantially proportional to a time integral of a product of a voltage and current of the electrical energy storage unit.

34. The energy control unit of claim 1, wherein:

the hybrid vehicle includes a motor controller operably coupled to the energy storage unit and operable to convert the stored energy of the energy storage unit into electrical energy for rotating the electric motor, and a generator rotatably coupled prime mover and operable to provide a source of electrical energy to the energy storage unit; and

the energy control unit is operable to (i) monitor an output of the energy storage unit; and

(ii) cause the source of electrical energy from the generator to deliver at least some of that electrical energy directly to the motor controller.

35. The energy control unit of claim 1, wherein:

the hybrid vehicle includes a motor controller operably coupled to the energy storage unit and operable to provide electrical energy for rotating the electric motor; and

the energy control unit is operable to cause the prime mover to operate at a rotational speed at or below an idle level when;

(i) the hybrid vehicle is at a stop; and

(ii) the electric motor and motor controller operate in a regeneration mode.

36. A drive system for a hybrid vehicle, comprising:

an electric motor operable to provide a source of drive power to the hybrid vehicle;

a motor controller operable to provide electrical energy for rotating the electric motor;

an energy storage unit operatively coupled to the motor controller to provide a source of energy to the motor controller;

an prime mover operatively operable to provide a source of rotational energy;

a charging system operable to convert the rotational energy from the prime mover into recharging energy for the energy storage unit; and

an energy control unit operable to control an amount of stored potential energy of the energy storage unit such that an energy level of the hybrid vehicle is maintained substantially at a desired magnitude, the energy level of the hybrid vehicle being a function of at least;

(i) mechanical kinetic energy of the hybrid vehicle;

(ii) mechanical potential energy of the hybrid vehicle; and

(iii) potential energy of the energy storage unit.

37. An energy control unit for a hybrid vehicle, the hybrid vehicle including (i) an electric motor operable to provide a source of drive power to the hybrid vehicle, (ii) a motor controller operable to provide electrical energy for rotating the electric motor, (iii) an energy storage unit operatively coupled to the motor controller to provide a source of energy to the motor controller, (iv) a prime mover operable to provide a source of rotational energy, and (v) a charging system operable to convert the rotational energy from the prime mover into recharging energy for the energy storage unit, the energy control unit comprising:

a positioning system operable to receive signals from an external source, the signals containing information concerning longitudinal and latitudinal positions of the hybrid vehicle;

a terrain prediction unit operable to estimate one or more grade angles and lengths of surfaces on which the hybrid vehicle may travel in the future based on the information concerning the longitudinal and latitudinal positions of the hybrid vehicle; and

a monitor operable to estimate a state of energy of the energy storage unit,

the energy control unit being operable to cause the charging system to at least one of provide and terminate the recharging power to the electrical energy storage unit as a function of at least one of;

(i) a state of energy from the monitor indicating that the state of energy of the energy storage unit has reached or fallen below a first threshold level, (ii) a state of energy from the monitor indicating that the state of energy of the energy storage unit has reached or exceeded a second threshold level, and (iii) the estimates of grade angles and lengths of the surfaces on which the hybrid vehicle may travel.

38. The energy control unit of claim 37, wherein the energy storage unit is taken from the group consisting of at least one battery, at least one ultra-capacitor, at least one lossless inductor, and at least one flywheel.

39. The energy control unit of claim 37, wherein the prime mover is taken from the group consisting of internal combustion engines, gas turbine engines, steam engines, and fuel cells.

40. The energy control unit of claim 37, wherein the positioning system is a Global Positioning System (GPS) unit operable to receive radio signals from a GPS satellite system.

41. The energy control unit of claim 37, wherein the energy control unit is operable to:

(i) cause the charging system to provide the recharging energy to the energy storage unit when the monitor indicates that the state of energy has reached or fallen below the first threshold level, and (ii) cause the charger to terminate recharging energy to the energy storage unit when the monitor indicates that the state of energy has reached or exceeded the second threshold level.

42. The energy control unit of claim 41, wherein the energy control unit is operable to automatically adjust when the charging system provides the recharging energy to the energy storage unit when the estimates of the grade angles and lengths of the surfaces on which the hybrid vehicle may travel indicate:

(i) that one or more downward grades may be reached using a quantum of energy from the energy storage unit which will not reduce the state of energy of the energy storage unit below a minimum threshold, and (ii) one or more of the lengths of the downward grades are sufficient to recover at least a substantial portion of the quantum of energy by converting mechanical potential energy of the hybrid vehicle into electrical energy.

43. The energy control unit of claim 41, wherein the energy control unit is operable to automatically adjust when the charging system provides the recharging energy to the energy storage unit when the estimates of the grade angles of the surfaces on which the hybrid vehicle may travel indicate that one or more upward grades may be reached having respective lengths which will require a quantum of energy from the energy storage unit sufficient to reduce the state of energy of the energy storage unit below at least the first threshold level.

44. The energy control unit of claim 41, wherein the energy control unit is operable to automatically adjust when the charging system provides the recharging energy to the energy storage unit when the estimates of the grade angles of the surfaces on which the hybrid vehicle may travel indicate:

(i) that one or more downward grades may be reached using a quantum of energy from the energy storage unit which will not reduce the state of energy of the energy storage unit below a minimum threshold, and (ii) one or more lengths of the downward grades are sufficient to recover enough energy to increase the state of energy of the energy storage unit to at least the second threshold level by converting mechanical potential energy of the hybrid vehicle into electrical energy.

45. The energy control unit of claim 37, wherein the terrain prediction unit is in communication with a database containing a plurality of grade angles and lengths of the grade angles which are indexed by and retrievable using the information concerning the longitudinal and latitudinal position of the hybrid vehicle.

46. The energy control unit of claim 45, wherein the terrain prediction unit estimates one or more grade angles and respective lengths of surfaces on which the hybrid vehicle may travel in the future based on the information concerning the longitudinal and latitudinal positions of the hybrid vehicle and at least one direction of travel.

47. The energy control unit of claim 46, wherein the terrain prediction unit estimates a future position of the hybrid vehicle based on:

(i) a given position of the hybrid vehicle, (ii) the direction of travel, and (iii) a velocity of the hybrid vehicle.

48. The energy control unit of claim 47, wherein the terrain prediction unit estimates the one or more grade angles and respective lengths of surfaces on which the hybrid vehicle may travel in the future by retrieving at least one of the plurality of grade angles and lengths from the database using the estimated future position of the hybrid vehicle as an index.

49. The energy control unit of claim 47, wherein the terrain prediction unit obtains the direction of travel from a direction sensor.

50. The energy control unit of claim 45, wherein the terrain prediction unit is in communication with a route memory containing travel information for one or more stored routes, and the travel information for a given one of the stored routes includes future positions of the hybrid vehicle when traveling the given route.

51. The energy control unit of claim 50, wherein the terrain prediction unit estimates the one or more grade angles and respective lengths of surfaces on which the hybrid vehicle may travel in the future by retrieving at least one of the plurality of grade angles and lengths from the database using the future positions of the hybrid vehicle as indices.

52. The energy control unit of claim 50, wherein the terrain prediction unit is operable to select one of the stored routes by monitoring one or more of the positions of the hybrid vehicle and estimating which of the stored routes substantially matches the monitored positions.

53. The energy control unit of claim 50, wherein the terrain prediction unit is operable to select one of the stored routes based on receiving instructional data from a driver of the hybrid vehicle.

54. The energy control unit of claim 53, wherein the instructional data includes a programmed seat position of the driver of the hybrid vehicle.

55. The energy control unit of claim 53, wherein the instructional data includes a request for directions to a destination from the driver of the hybrid vehicle, and the terrain prediction unit is operable to select one of the stored routes which may direct the driver of the hybrid vehicle to the destination.